Transdermal delivery techniques which utilize electrical signal for delivering a drug to a patient for systemic distribution by blood flow are well known. In particular, iontophoretic techniques have demonstrated utility in the transdermal delivery of ions of soluble salts, including peptides.
Since the introduction of the isolated perfused porcine skin flap (IPPSF), iontophoretic studies of drug penetration, absorption and toxicity have received increasing attention. However, the major limitation of utilizing IPPSF in iontophoretic studies is that only single test compounds can be evaluated in a single IPPSF according to conventional techniques. The cost of performing extensive iontophoretic evaluations of multiple compounds is prohibitively large due to the costs incident in the procurement and preparation of multiple IPPSFs. At present, no alternative in vitro model system is available, and moral considerations limit the desirability of evaluating drug penetration, absorption and particularly toxicity in vivo. As a result, there is a need in the art for a method of efficiently and cost-effectively evaluating the penetration, absorption, and toxicity of a multiplicity of compositions using a single iontophoretic device. Previously, it was believed that the simultaneous iontophoretic delivery of a multiplicity of compounds by adjacent electrodes would not be possible due to electrical and chemical interference from adjacent electrodes.
Accordingly, it is an object of the present invention to provide an iontophoretic device useful for evaluating the penetration, absorption, and toxicity of compositions by iontophoresis. It is a further object of the present invention to provide an iontophoretic device useful for evaluating a multiplicity of compositions using iontophoresis.